Comprehensive control of diseases and insect pests of onion at seedling stage

In case of rainy weather, onion diseases and insect pests will occur seriously during seedling stage, and attention should be paid to prevention and control work in advance. Select seedbeds and select fields that have been rotated with non-onion and garlic crops for more than 2 years as seedbeds. Be careful not to select fields where herbicides are used excessively in previous crops to avoid onion stiff seedlings or dead seedlings. Deepen the drainage ditch, insist on deep ditch and high ridge, open high-standard drainage ditch around the seedbed, so that there is no accumulated water in the bed after rain, and reduce the groundwater level and soil humidity in the bed. In case of dry weather, spray can be used, avoid flooding. Before soil preparation, 48% chlorpyrifos emulsifiable concentrate mixed with 30kg fine soil per mu can control white grubs and cutworms. After sowing, use 48% chlorpyrifos emulsifiable concentrate 50ml per mu to mix fried bran or bean cake 2.5kg to make bait, spread around the seedbed in the evening, can trap mole cricket and old cutworm transferred to the seedbed outside the bed. Disinfection of soil: 300g of 45% Penta-Bromobacterium powder (containing 30% quintozene and 15% bromothalonil) and 40~ 50kg of fine soil are mixed evenly in each mu of seedbed, one third of which is scattered on the smooth surface of the bed, and two thirds of which are covered with seeds, which can alleviate the disease of seedling stage. 10% Imidacloprid WP 1000 times and 2% Ningnanmycin 500 times were sprayed twice to control aphids and thrips, and yellow dwarf disease caused by their transmission. 3.2% Oxidacloprid·Metalaxone was used at 1~2 leaf stage. 800 times solution of (containing 2.6% hymexyl, 0.6% metalaxyl) aqueous solution and 600 times solution of 25% metalaxyl WP were sprayed to control damping-off disease and bacterial wilt, and sprayed again after 7 days; 3000 times solution of Aimiao (30% diphenate·procyclin EC) was sprayed to control anthracnose at the beginning of disease, and 1000 times solution of 50% procymidone WP was sprayed to control gray mold, and sprayed again after 10 days.